21488461 has 4 divisors (see below), whose sum is σ = 21508252. Its totient is φ = 21468672.

The previous prime is 21488431. The next prime is 21488477. The reversal of 21488461 is 16488412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6325225 + 15163236 = 2515^2 + 3894^2 .

It is a cyclic number.

It is not a de Polignac number, because 21488461 - 2⁵ = 21488429 is a prime.

It is a super-2 number, since 2×21488461² = 923507912297042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21488431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8166 + ... + 10471.

It is an arithmetic number, because the mean of its divisors is an integer number (5377063).

Almost surely, 2^21488461 is an apocalyptic number.

It is an amenable number.

21488461 is a deficient number, since it is larger than the sum of its proper divisors (19791).

21488461 is a wasteful number, since it uses less digits than its factorization.

21488461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19790.

The product of its digits is 12288, while the sum is 34.

The square root of 21488461 is about 4635.5647983822. The cubic root of 21488461 is about 278.0151338310.

It can be divided in two parts, 2148 and 8461, that added together give a square (10609 = 103²).

The spelling of 21488461 in words is "twenty-one million, four hundred eighty-eight thousand, four hundred sixty-one".